In high-resolution imaging, the use of coherent illumination leads to well-known problems of speckle and loss of resolution. This problem has been studied particularly in the context of microscopy, as described by Born and Wolf in Principles of Optics (Seventh Edition, Cambridge University Press, 1999), in Chapter 10, which is incorporated herein by reference. On page 597, the authors note that the resolution of an image taken using coherent illumination is determined by a factor m=NAC/NAO, wherein NAC is the numerical aperture of the lens used to focus the illumination onto the image plane (the condenser, in microscopy terms), and NAO is the numerical aperture of the imaging objective. For optimal image resolution, it is desirable that m be roughly in the range between 1 and 1.5.